I have been using Apalis IMX6 module on custom evaluation board, where TTL comunication port is used as a UART 4 connected to UART4_RXD and UART4_TXD, but it
s not working (not sending nor receiving). Probably its a system fault (WEC2013 v. 1.1b2) to be more precise missing keys in registry because UART1, 2, 3 works (they have their own keys in registry). How can I make it work?
If registry entries are missing (and they are missing if you are using our standard image) you should get an error from CreateFile when trying to access COM4.
You may add the following entries to registry to enable it:
[HKEY_LOCAL_MACHINE\Drivers\BuiltIn\COM4] "DeviceArrayIndex"=dword:3 "IoLen"=dword:D4 "Prefix"="COM" "Dll"="csp_serial.dll" "Index"=dword:4 "Order"=dword:2 [HKEY_LOCAL_MACHINE\Drivers\BuiltIn\COM4\Unimodem] "Tsp"="Unimodem.dll" "DeviceType"=dword:0 "FriendlyName"="COM4 UNIMODEM" "DevConfig"=hex: 10,00, 00,00, 05,00,00,00, 10,01,00,00, 00,4B,00,00, 00,00, 08, 00, 00, 00,00,00,00
If you are using the standard TX/RX pins documented in the datasheet, that should be enough.
If you need additional pins to be multiplexed you can use the multiplexing options described here: